The present invention relates to a method and system for converting or retrofitting manually operated, already installed flush valves.
In toilet rooms it is common to use various types of flushing systems for flushing urinals or toilet bowls (also commonly referred to as toilets). A first type of a conventional toilet flush system uses water accumulated in a water storage tank. This system usually includes a float operated intake valve mounted at a water intake pipe for delivering water into the water tank. The intake valve includes a rod connected to a float that acts to close the intake valve when there is a predefined water level in the water tank. At the bottom of the water tank, there is a tank outlet fixture through which water from the tank is discharged into a toilet bowl when a flush handle is activated to flush the toilet. During and after the flushing action, the float drops below a closing position, which in turn opens the intake valve and water flows into the tank until water in the tank reaches the predefined level. At the predefined level, the float floats up to the closing position that in turn closes the intake valve.
A second type of a conventional toilet flush system doesn't use the water storage tank, but uses water for flushing directly from a water supply line. This flush system uses a flush valve (known as a “Flushometer”) that may be a diaphragm-type valve or a piston-type valve. The flush valve can be manually activated by depressing a handle (or can be automatically activated by a sensor) to control flushing a toilet or a urinal. In these systems the flush valve controls a pilot section that is located somewhat above the diaphragm (in the valve diaphragm-type valve) or the piston (in the piston-type valve). The pilot section receives water through one or several control orifices. The valve controls pressure in the pilot section, which in turn activates water flow from the supply line to the toilet or urinal creating the flush action.
In the diaphragm-type valve or the piston-type valve, the pilot section has the control orifices with a quasi-fixed supply rate by virtue of maintaining a hydraulic condition known as “choked flow condition”. The pilot section also includes a drain valve, which is activated by the user handle to lower pressure in the pilot section. Upon activation of the drain valve (which has a flow through rate much higher than the control orifice feed rate), the pilot chamber is depleted, resulting in the opening of the main flow passage that facilitates the main flushing flow. The main passage will remain open as long as it takes for the pilot chamber to refill (after handle release followed by drain valve reseal) through the pilot orifice. The water pressure in the pilot chamber closes the main passage to seal the main water dosage, as described in detail in connection with FIG. 1.
The diaphragm-type flush valves and the piston-type flush valve were described in numerous publications and patents. For example, various diaphragm-type flush valves are described in U.S. Pat. Nos. 5,125,621; 5,456,279; 6,216,730; or PCT publication WO91/17380, and the piston-type flush valve is described in U.S. Pat. No. 5,881,993.
FIG. 1 shows a prior art diaphragm-type flush valve for flushing a toilet or a urinal. Flush valve 10 includes a diaphragm 12 disposed on a valve seat 14 formed on a lower part 16 of the valve body. The valve body also includes an upper body part 18 with a dome or cap 20 that clamps diaphragm 12 against lower body part 16 using an upper housing 22. In the closed position, water has entered by an inlet pipe 24 into an annular main chamber 26 surrounding a cylindrical inner wall 30 of lower body part 16. The sealing action of diaphragm 12 prevents water in main chamber 26 from flowing from main chamber 26 into an outlet conduit 32. That is, diaphragm 12 seals main passage 14 in the closed position.
Flush valve 10 includes a pilot chamber 36 formed by the dome 20 and diaphragm 12. Diaphragm 12 includes a control orifice 34, which enables water flow from main chamber 26 to pilot chamber 36 and thus causes pressure equalization between main chamber 26 and pilot chamber 36 separated by diaphragm 12. When the pressure is equalized, there is a net force on diaphragm 12 from pilot chamber 36 downward (on the diaphragm 12) since the diaphragm area in pilot chamber 36 is larger than the opposing diaphragm area in main chamber 26. The downward oriented net force keeps the valve closed by sealing main passage 14. To open flush valve 10, a pilot valve provides a pressure-relief mechanism that lowers the water pressure in pilot chamber 36. The pilot valve includes a pilot valve member 50 with a rod portion 58 displaceable by a plunger 56 connected to a manual flush handle 54. Pilot valve member 50 includes a pilot seat 52 for sealing against in the diaphragm plate 38.
Operation of handle 54 causes displacement of plunger 56 against rod portion 58 of pilot valve member 50. When pilot valve member 50 is displaced, water flows with minimal flow resistance from pilot chamber 36 near pilot seat 52 through the relief opening 49, while control orifice 34 in the diaphragm plate 38 imposes considerable resistance to the compensating flow from main chamber 26 through orifice 34 to pilot chamber 36. Consequently, the pressure in pilot chamber 36 decreases significantly below the pressure in main chamber 26 so that the force exerted by pressure in pilot chamber 36 is lower than that exerted by the pressure in main chamber 26. Thus, the portion of the diaphragm plate 38 located interior to its clamped portion 59 flexes upward, rising off main valve seat 14 (i.e., main passage 14); this opens the valve and water flows from main chamber 26 to water output 32.
When a user releases flush handle 54, pilot valve 50 returns to its position on pilot valve seat 52, but the pressure in the pilot chamber 36 does not immediately return to the level in the main chamber 26 because the pressure-equalizing flow from main chamber 26 to pilot chamber 36 is restricted by the small size of control orifice 34. This delay in pressure equalization is desirable because for a predetermined length of time water flows from output 32 to the connected toilet or urinal. Ultimately, however, the water flow via control orifice 34 equalizes the pressure between main chamber 26 and pilot chamber 36 to the point at which the downward force on main diaphragm 12 overcomes the upward force, and the valve closes. This entire flushing cycle is repeated by moving handle 54.
There are several existing design approaches used for converting (i.e., retrofitting) the existing manual flush valves to sensory-activated electronically controlled automatic valves. There is a top cover assembly that replaces upper housing 22 (shown in FIG. 1). The top cover system includes an electronic sensory module, a battery pack, and electronics for controlling a bi-stable solenoid that acts upon a pilot valve. The pilot valve in turn controls the main diaphragm valve. The top cover conversion system usually includes a new main diaphragm assembly that replaces main diaphragm 12 (used in the manual system shown in FIG. 1). These types of conversion systems are described in U.S. Pat. Nos. 5,169,118 and 5,244,179.
Another type of a sensory controlled flushing device (known as a “side mount” conversion device) is described, for example, in U.S. Pat. Nos. 5,431,181, 5,680,879 and 6,056,261. The side mount device includes a sensory module, a battery pack, an electric motor, and an activation plunger that is mounted onto a common housing. Specifically, in the “side mount” device, the activation plunger is mounted on to the flush valve assembly after first removing a manual handle (e.g., flush handle 54 in FIG. 1). Upon receiving a flush command from the sensory module, the electronics activates the movement of the replacement plunger thereby activating the pilot valve, which in turn starts the flush cycle.
The installation of the “side mount” conversion (retrofit) device requires removal and replacement of the manual flush handle. The handle removal frequently requires breaking the existing water seal for installation. Specifically, to install some of these devices, a person may need to turn the water supply off, dismantle portions of the flush valve, install the device, reestablish the water seal, and then turn the water back on. Perhaps, even if the water supply doesn't need to be turned off, the person needs to remove the manual flush handle. Thus, in either case, this installation requires the job to be performed by a qualified professional.
Importantly, some conversion or retrofit devices do not have a truly manual override mechanism (i.e., the ability to override the sensory control to start a flushing cycle if there is no electrical power available). These systems usually have an electrical switch that bypasses the optical sensor to trigger flushing electronically, but this cannot be done during power source failure. That is, such conversion device cannot start a flushing cycle (sensory or “manual” by depressing a switch triggering a solenoid) during power failure.
Therefore, there is still a need for devices for converting or retrofitting manually operated, already installed flush valves used in toilet rooms.